The present invention is based on a micro-actuator having a bending element and at least one force element Arranged on the bending element and having a variable length relative to the bending element. U.S. Pat. No. 5,058,856 describes a micro-valve having a micro-actuator designed as a bending element. A force element is arranged on the bending element and has a length relative to the bending element which varies as a result of heating. A frequency-analog accelerometer constructed from three beams is described in D. W. Satchell et al., "A Thermally-Excited Silicon Accelerometer", Sensors and Actuators, Vol. 17, pp. 241-245 (May 3, 1989) ("the Satchell article"). The central beams are thermomechanically excited into oscillation and thus likewise represent a micro-actuator.
A micro-pump as a drive for an ink-jet nozzle is described in K. E. Petersen, "Silicon as a Mechanical Material", Proceedings of the IEEE, Vol. 70, No. 5, pp. 420-457 (May 1982) ("the Petersen article"). As FIG. 21 on page 433 of the Petersen article shows, a piezo-electric crystal is fitted to a membrane as the force element. German Patent Application No. 42 20 226 describes magnetostrictive force elements arranged on bending elements.
However, in each of these known devices, the characteristic of the bending element disadvantageously varies with changes in environmental temperature. Hence, a micro-actuator including a bending element having a constant characteristic over wide temperature ranges thereby avoiding the need to provide a constant temperature environment is desired.